Dual clutch transmission

ABSTRACT

A transmission includes an input member, an output member, first and second shafts, first and second countershafts, a plurality of co-planar gear sets, and a plurality of torque transmitting devices. The torque transmitting devices include a plurality of synchronizer assemblies and a dual clutch assembly. The transmission is operable to provide at least one reverse speed ratio and a plurality of forward speed ratios between the input member and the output member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/172,041, filed on Apr. 23, 2009, which is hereby incorporated in itsentirety herein by reference.

TECHNICAL FIELD

The present disclosure relates to transmissions and more particularly toa compact, dual clutch transmission having three axes to establish sixgear speeds of which one could be a reverse gear speed.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission having countershafts and co-planargear sets uses countershaft gears with a different, dedicated gear pairor set to achieve each forward speed ratio. Accordingly, the totalnumber of gears required in this typical design is two times the numberof forward speeds, plus three for reverse. This necessitates a largenumber of required gear pairs, especially in transmissions that have arelatively large number of forward speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needin the art for a transmission having improved packaging while providingdesirable gear ratios and torque ranges.

SUMMARY

The present invention provides a transmission having an input member, anoutput member, first and second shaft members, first and secondcountershafts, a plurality of co-planar gear sets and a plurality oftorque transmitting devices. The torque transmitting devices include aplurality of synchronizer assemblies and a dual clutch assembly. Thetransmission is operable to provide at least one reverse speed ratio anda plurality of forward speed ratios between the input member and theoutput member.

In one aspect of the present invention, the transmission includesbetween four and six co-planar gear sets.

In yet another aspect of the present invention, the transmissionincludes five synchronizer assemblies.

In yet another aspect of the present invention, one of the synchronizerassemblies is a two-way synchronizer.

In yet another aspect of the present invention, four of the synchronizerassemblies are one-way synchronizers.

In yet another aspect of the present invention, the transmission isoperable to provide at least five forward speed ratios.

The above features and advantages and other features and advantages ofthe present invention are readily apparent from the following detaileddescription of the best modes for carrying out the invention when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic diagram of an embodiment of a five speedtransmission, in accordance with the present invention;

FIG. 2 is a schematic diagram of an embodiment of a five speedtransmission illustrating synchronizer locations, in accordance with thepresent invention;

FIG. 3 is a schematic diagram of another embodiment of a five speedtransmission, in accordance with the present invention;

FIG. 4 is a schematic diagram of another embodiment of a five speedtransmission illustrating synchronizer locations, in accordance with thepresent invention;

FIG. 5 is a schematic diagram of still another embodiment of a fivespeed transmission, in accordance with the present invention;

FIG. 6 is a schematic diagram of an still another embodiment of a fivespeed transmission illustrating synchronizer locations, in accordancewith the present invention;

FIG. 7 is a schematic diagram of still another embodiment of a fivespeed transmission, in accordance with the present invention; and

FIG. 8 is a schematic diagram of an still another embodiment of a fivespeed transmission illustrating synchronizer locations, in accordancewith the present invention.

DESCRIPTION

Referring to FIG. 1, a multiple speed transmission is generallyindicated by reference number 10. The transmission 10 includes an inputmember 12 and a gearing arrangement 20. The input member 12 may beseparate from the transmission 10 and form part of or be connected witha flywheel or other output from an engine (not shown). The gearingarrangement 20 includes various shafts or members, co-planarintermeshing gear sets, a dual clutch assembly, and selectivelyengageable synchronizers, as will be described herein. For example, thegearing arrangement 20 includes a first transmission input shaft ormember 22, a second transmission input shaft or member 24, a firstcountershaft 28 and a second countershaft 30. The second shaft or member24 is a sleeve shaft that is concentric with and overlies the firstshaft or member 22. The first and second countershafts 28, 30 are spacedapart from and parallel with the first and second shaft members 22, 24.Moreover, the first and second countershafts 28, 30 are connectablethrough additional gears and/or shafts (not shown) to a final driveassembly (not shown) that is configured to drive a pair of road wheels(not shown). The first and second shafts 22, 24 define a first axis ofrotation, the first countershaft 28 defines a second axis of rotationand the second countershaft 30 defines a third axis of rotation.

A dual clutch assembly 32 is connectable between the input member 12 andthe first and second shaft members 22, 24. The dual clutch assembly 32includes a clutch housing 34 connectable for common rotation with theinput member 12. The dual clutch assembly 32 could be either a dry or awet clutch assembly. Further, the dual clutch assembly 32 has first andsecond clutch elements or hubs 36 and 38. Clutch elements 36 and 38together with the clutch housing 34 are configured to form a frictionclutch, as is known in the art as a dual clutch. More specifically,clutch elements 36, 38 and the clutch housing 34 have friction platesmounted thereon or otherwise coupled thereto that interact to form afriction clutch. The clutch element 36 is connected for common rotationwith the first shaft or member 22 and the clutch element 38 is connectedfor common rotation with the second shaft or member 24. Thus, selectiveengagement of clutch element 36 with the clutch housing 34 connects theinput member 12 for common rotation with the first shaft member 22.Selective engagement of clutch element 38 with the clutch housing 34connects the input member 12 for common rotation with the second shaftmember 24.

The gearing arrangement 20 also includes a plurality of co-planar,intermeshing gear sets 40, 50, 60, 70, 80, and 90. Co-planar gear sets40, 50, 60, 70, 80, and 90 include intermeshing gear pairs: gear 42 andgear 44, gear 52 and gear 54, gear 62 and gear 64, gear 72 and gear 74,gear 82 and gear 84, and gear 92 and gear 94, respectively. In anembodiment of the present invention, gears 42 and 52 are eitherrotatably fixed for common rotation with the second shaft member 24 orare selectively connectable for common rotation with the second shaftmember 24. Gears 62, 72, 82, and 92 are either rotatably fixed forcommon rotation with the first shaft member 22 or are selectivelyconnectable for common rotation with the first shaft member 22. Gears 54and 64 are either rotatably fixed for common rotation with the secondcountershaft 30 or are selectively connectable for common rotation withthe second countershaft 30. Further, gears 44, 74, 84, and 94 are eitherrotatably fixed for common rotation with the first countershaft 28 orare selectively connectable for common rotation with the firstcountershaft 28. The individual gears of co-planar gear sets 40, 50, 60,70, 80, and 90 are independently and selectively connectable for commonrotation with the first shaft member 22, second shaft member 24, firstcountershaft 28 or second countershaft 30 by synchronizer assemblies, aswill be further described hereinafter. Of course, the present inventioncontemplates other selectively actuatable devices other thansynchronizers for connecting gears to shafts.

Referring now to FIG. 2, another embodiment of a multiple speedtransmission is generally indicated by reference number 100. Thetransmission 100 includes an input shaft or member 112 and an outputgear or member 114. The input member 112 is continuously connected withan engine (not shown) or other torque producing machine to provide adriving torque to input member 112. The output member 114 rotatablydrives a final drive assembly 116. More specifically, the final driveassembly 116 includes a differential gear set coupled to and supportedin a differential housing 117. Differential housing 117 is coupled toand is rotatably driven by output member 114. Further, differentialhousing 117 transfers torque delivered by output member 114 to thedifferential gear set that is rotatably coupled to first and second sideaxles 118, 119, and on to road wheels (not shown) coupled to side axles118, 119.

The transmission 100 includes a gearing arrangement 120 that is at leastpartially enclosed by a housing 121. The housing 121 includes end walls123 and 125. End wall 123 is located on a front or side of thetransmission 100 proximate the dual clutch assembly 132 and end wall 125is located on an opposite side of the transmission housing 121 than endwall 125. As in the embodiment described above, the gearing arrangement120 of transmission 100 includes a first transmission input shaft ormember 122, a second transmission input shaft or member 124, a firstcountershaft 128 and a second countershaft 130. The second shaft ormember 124 is a sleeve shaft that is concentric with and overlies thefirst shaft or member 122. The first and second countershafts 128, 130are each spaced apart from and parallel with the first and second shaftmembers 122,124. The first and second shafts 122,124 define a first axisof rotation, the first countershaft 128 defines a second axis ofrotation and the second countershaft 130 defines a third axis ofrotation.

A dual clutch assembly 132 is connectable between the input member 112and the first and second shaft members 122, 124. The dual clutchassembly 132 includes a clutch housing 134 connectable for commonrotation with the input member 112. Further, the dual clutch assembly132 has first and second clutch elements or hubs 136 and 138. Clutchelements 136 and 138 together with the clutch housing 134 are configuredto form a friction clutch, as is known in the art as a dual clutch. Morespecifically, clutch elements 136, 138 and the clutch housing 134 havefriction plates mounted thereon or otherwise coupled thereto thatinteract to form a friction clutch. The clutch element 136 is connectedfor common rotation with the first shaft or member 122 and the clutchelement 138 is connected for common rotation with the second shaft ormember 124. Thus, selective engagement of clutch element 136 with theclutch housing 134 connects the input member 112 for common rotationwith the first shaft member 122. Selective engagement of clutch element138 with the clutch housing 134 connects the input member 112 for commonrotation with the second shaft member 124.

The gearing arrangement 120 also includes a plurality of co-planar,intermeshing gear sets 140, 150, 160, 170, 180, and 190. Co-planar gearset 140 includes gear 142 and gear 144. Gear 142 is rotatably fixed andconnected for common rotation with the second shaft 124 and intermesheswith gear 144. Gear 144 is selectively connectable for common rotationwith the first countershaft member 128. Gear set 140 is disposedadjacent the end wall 123.

Co-planar gear set 150 includes gear 152 and gear 154. Gear 152 isrotatably fixed and connected for common rotation with the second shaftmember 124 and intermeshes with gear 154. Gear 154 is selectivelyconnectable for common rotation with the second countershaft 130. Gearset 150 is positioned adjacent gear set 140.

Co-planar gear set 160 includes gear 162 and gear 164. Gear 162 isrotatably fixed and connected for common rotation with the first shaftmember 122 and intermeshes with gear 164. Gear 164 is selectivelyconnectable for common rotation with the second countershaft 130. Gearset 160 is disposed adjacent gear set 150.

Co-planar gear set 170 includes gear 172 and gear 174. Gear 172 isrotatably fixed and connected for common rotation with the first shaft122 and intermeshes with gear 174. Gear 174 is selectively connectablefor common rotation with the first countershaft member 128. Gear set 170is located adjacent gear set 160.

Co-planar gear set 180 includes gear 182 and gear 184. Gear 182 isrotatably fixed and connected for common rotation with the first shaftmember 122 and intermeshes with gear 184. Gear 184 is selectivelyconnectable for common rotation with the first countershaft 128.

Co-planar gear set 190 includes gear 192, gear 194, and gear 196. Gear192 is rotatably fixed and connected for common rotation with the firstshaft member 122 and intermeshes with gear 196. Gear 196 is supported onthe first countershaft 128, however, gear 196 is not rotationallycoupled to the first countershaft 128. Gear 196 intermeshes with gear194. Gear 194 is selectively connectable for common rotation with thesecond countershaft 130. Gear set 190 is positioned between gear set 180and end wall 125 of transmission 100. It should be noted that gear sets140, 150, 160, 170, 180, and 190 can be rearranged in sequence and notdeviate from the intent of the invention.

Further, a first countershaft transfer gear 195 is rotatably fixed andconnected for common rotation with the first countershaft member 128. Asecond countershaft transfer gear 197 is rotatably fixed and connectedfor common rotation with the second countershaft member 130. Firstcountershaft transfer gear 195 is configured to mesh with output member114 and the second countershaft transfer gear 197 is configured to meshwith output member 114. However, the first countershaft transfer gear195 and the second countershaft transfer gear 197 do not mesh with eachother. The first countershaft transfer gear 195 is disposed between gear144 and end wall 123 of the transmission housing 121. The secondcountershaft transfer gear 197 is disposed between gear 146 and end wall123 of the transmission housing 121. The output member 114 is co-planarwith first and second countershaft transfer gears 195, 197 andpositioned between the gear set 140 and end wall 123 of the transmissionhousing 121.

The transmission 100 further includes a plurality of selectivelyactuatable synchronizer assemblies 199A, 199B, 199C, 199D, and 199E.Synchronizers 199A, 199B, 199C, and 199D are single sided synchronizersthat generally include a shift fork (not shown) that is bi-directionallytranslated by an actuator (not shown) into either an engaged position ora neutral or disengaged position. In the present embodiment,synchronizer 199A is selectively actuatable to connect gear 144 forcommon rotation with the first countershaft 128, synchronizer 199B isselectively actuatable to connect gear 154 for common rotation with thesecond countershaft 130, synchronizer 199C is selectively actuatable toconnect gear 164 for common rotation with the second countershaft 130,and synchronizer 199D is selectively actuatable to connect gear 194 forcommon rotation with the second countershaft 130. Synchronizer 199E is adouble sided synchronizer and generally includes a shift fork (notshown) that is bi-directionally translated by an actuator (not shown)into at least two engaged positions and a neutral or disengagedposition. In the present embodiment, synchronizer 199E is selectivelyactuatable to connect for common rotation gear 174 with the firstcountershaft 128 and is selectively actuatable to connect for commonrotation gear 184 with the first countershaft 128.

The transmission 100 is capable of transmitting torque from the inputshaft 112 to the output member 114 in at least five forward torqueratios and at least one reverse torque ratio. Each of the forward torqueratios and the reverse torque ratio is attained by selective engagementof the dual clutch assembly 132 and one or more of the synchronizerassemblies 199A-E. Those skilled in the art will readily understand thata different speed ratio is associated with each torque ratio.

It should be appreciated that each individual gear set 140, 150, 160,170, 180, and 190 provides one or more forward and/or reverse gearratios upon selective engagement of the synchronizer assemblies 199A-E.However, which synchronizer and which gear set are associated with aparticular forward or reverse speed ratio may vary without departingfrom the scope of the present invention.

For example, to establish the reverse torque ratio, clutch element 136is engaged to couple the input member 112 with the first shaft 122 andsynchronizer 199D is engaged to connect gear 194 to the secondcountershaft 130. More specifically, input torque from the input shaft112 is transferred through the dual clutch assembly 132 to the firstshaft 122, through gear 192 to gear 196, through gear 196 to gear 194,from gear 194 to synchronizer 199D, from synchronizer 199D to secondcountershaft 130, from second countershaft 130 to transfer gear 197,from transfer gear 197 to output gear 114 and from output gear 114 todifferential housing 117 of final drive assembly 116.

To establish a first forward torque ratio (i.e. a 1st gear), clutchelement 136 is engaged to couple the input member 112 with the firstshaft member 122 and synchronizer 199C is activated to couple gear 164to the second countershaft 130. Input torque from the input member 112is transferred through the dual clutch assembly 132 to the first shaftmember 122 to gear 162. Gear 162 transfers torque to gear 164 whichtransfers the torque to the second countershaft 130 through synchronizer199C, from the second countershaft 130 to transfer gear 197, fromtransfer gear 197 to output gear 114, and from output gear 114 todifferential housing 117 of final drive assembly 116.

To establish a second forward torque ratio (i.e. a 2nd gear), clutchelement 138 is engaged to couple the input member 112 to the secondshaft 124 which rotates gear 142 and synchronizer 199A is activated tocouple gear 144 to the first countershaft member 128. Accordingly, inputtorque from the input member 112 is transferred through the dual clutchassembly 132 to the second shaft member 124 to gear 142. Gear 142transfers torque to gear 144 which transfers the torque to the firstcountershaft 128 through synchronizer 199A, from the first countershaft128 to transfer gear 195, from transfer gear 195 to output gear 114 andfrom output gear 114 to differential housing 117 of final drive assembly116.

To establish a third forward torque ratio (i.e. a 3rd gear), clutchelement 136 is engaged to couple the input member 112 to the first shaft122 which rotates gear 182 and synchronizer 199E is engaged to couplegear 184 to the first countershaft 128. Accordingly, input torque fromthe input member 112 is transferred through the dual clutch assembly 132to the first shaft 122 to gear 182. Gear 182 transfers torque to gear184 which transfers the torque to the first countershaft 128 throughsynchronizer 199E, from the first countershaft 128 to transfer gear 195,from transfer gear 195 to output gear 114 and from output gear 114 todifferential housing 117 of final drive assembly 116.

To establish a fourth forward torque ratio (i.e. a 4th gear), clutchelement 138 is engaged to couple the input member 112 to the secondshaft member 124 which rotates gear 152 and synchronizer 199B isactivated to couple gear 154 to the second countershaft 130. Thus, inputtorque from the input member 112 is transferred through the dual clutchassembly 132 to the second shaft 124 to gear 152. Gear 152 transferstorque to gear 154 which transfers the torque to the second countershaft130 through synchronizer 199B, from the second countershaft 130 totransfer gear 197, from transfer gear 197 to output gear 114 and fromoutput gear 114 to differential housing 117 of final drive assembly 116.

To establish a fifth forward torque ratio (i.e. a 5th gear), clutchelement 136 is engaged to couple the input member 112 to the first shaft122 which rotates gear 172 and synchronizer 199E is activated to couplegear 174 to the first countershaft 128. Thus, input torque from theinput member 112 is transferred through the dual clutch assembly 132 tothe first shaft 122 to gear 172. Gear 172 transfers torque to gear 174which transfers the torque to the first countershaft 128 throughsynchronizer 199E, from the first countershaft 128 to transfer gear 195,from transfer gear 195 to output gear 114 and from output gear 114 todifferential housing 117 of final drive assembly 116.

Again, it should be appreciated that any one of the gear sets 140, 150,160, 170, 180, and 190 may be changed to produce a certain forward andreverse torque ratio without departing from the scope of the presentinvention.

The present invention contemplates that a variety of torque ratios(i.e., the ratio of torque of the output member 114 to the input member112) are achievable through the selection of tooth counts of the gearsof the transmission 100. This arrangement provides the opportunity toachieve reduced transmission length in comparison with othertransmissions.

Referring to FIG. 3, a multiple speed transmission is generallyindicated by reference number 200. The transmission 200 includes aninput member 212 and a gearing arrangement 220. The gearing arrangement220 includes various shafts or members, co-planar intermeshing gearsets, a dual clutch assembly, and selectively engageable synchronizers,as will be described herein. For example, the gearing arrangement 220includes a first transmission input shaft or member 222, a secondtransmission input shaft or member 224, a first countershaft 228 and asecond countershaft 230. The second shaft or member 224 is a sleeveshaft that is concentric with and overlies the first shaft or member222. The first and second countershafts 228, 230 are spaced apart fromand parallel with the first and second shaft members 222, 224. Moreover,the first and second countershafts 228, 230 are connectable throughadditional gears and/or shafts (not shown) to a final drive assembly(not shown) that is configured to drive a pair of road wheels (notshown). The first and second shafts 222, 224 define a first axis ofrotation, the first countershaft 228 defines a second axis of rotationand the second countershaft 230 defines a third axis of rotation.

A dual clutch assembly 232 is connectable between the input member 212and the first and second shaft members 222, 224. The dual clutchassembly 232 includes a clutch housing 234 connectable for commonrotation with the input member 212. The dual clutch assembly 232 couldbe either a dry or a wet clutch assembly. Further, the dual clutchassembly 232 has first and second clutch elements or hubs 236 and 238.Clutch elements 236 and 238 together with the clutch housing 234 areconfigured to form a friction clutch, as is known in the art as a dualclutch. More specifically, clutch elements 236, 238 and the clutchhousing 234 have friction plates mounted thereon or otherwise coupledthereto that interact to form a friction clutch. The clutch element 236is connected for common rotation with the first shaft or member 222 andthe clutch element 238 is connected for common rotation with the secondshaft or member 224. Thus, selective engagement of clutch element 236with the clutch housing 234 connects the input member 212 for commonrotation with the first shaft member 222. Selective engagement of clutchelement 238 with the clutch housing 234 connects the input member 212for common rotation with the second shaft member 224.

The gearing arrangement 220 also includes a plurality of co-planar,intermeshing gear sets 240, 250, 260, 270, and 280. Co-planar gear sets240, 250, 260, 270, and 280 include intermeshing gear pairs: gear 242,gear 244, and gear 246, gear 252 and gear 254, gear 262 and gear 264,gear 272 and gear 274, and gear 282 and gear 284, respectively. In anembodiment of the present invention, gear 242 is either rotatably fixedfor common rotation with the second shaft member 224 or is selectivelyconnectable for common rotation with the second shaft member 224. Gears252, 262, 272 and 282 are either rotatably fixed for common rotationwith the first shaft member 222 or are selectively connectable forcommon rotation with the first shaft member 222. Gears 246 and 254 areeither rotatably fixed for common rotation with the second countershaft230 or are selectively connectable for common rotation with the secondcountershaft 230. Further, gears 244, 264, 274, and 284 are eitherrotatably fixed for common rotation with the first countershaft 228 orare selectively connectable for common rotation with the firstcountershaft 228. The individual gears of co-planar gear sets 240, 250,260, 270, 280 are independently and selectively connectable for commonrotation with the first shaft member 222, second shaft member 224, firstcountershaft 228 or second countershaft 230 by synchronizer assemblies,as will be further described hereinafter. Of course, the presentinvention contemplates other selectively actuatable devices other thansynchronizers for connecting gears to shafts.

Referring now to FIG. 4, another embodiment of a multiple speedtransmission is generally indicated by reference number 300. Thetransmission 300 includes an input shaft or member 312 and an outputgear or member 314. The input member 312 is continuously connected withan engine (not shown) or other torque producing machine to provide adriving torque to input member 312. The output member 314 rotatablydrives a final drive assembly 316. More specifically, the final driveassembly 316 includes a differential gear set coupled to and supportedin a differential housing 317. Differential housing 317 is coupled toand is rotatably driven by output member 314. Further, differentialhousing 317 transfers torque delivered by output member 314 to thedifferential gear set that is rotatably coupled to first and second sideaxles 318, 319, and on to road wheels (not shown) coupled to side axles318, 319.

The transmission 300 includes a gearing arrangement 320 that is at leastpartially enclosed by a housing 321. The housing 321 includes end walls323 and 325. End wall 323 is located on a front or side of thetransmission 300 proximate a dual clutch assembly 332 and end wall 325is located on an opposite side of the transmission housing 321 than endwall 325. As in the embodiment described above, the gearing arrangement320 of transmission 300 includes a first transmission input shaft ormember 322, a second transmission input shaft or member 324, a firstcountershaft 328 and a second countershaft 330. The second shaft ormember 324 is a sleeve shaft that is concentric with and overlies thefirst shaft or member 322. The first and second countershafts 328, 330are each spaced apart from and parallel with the first and second shaftmembers 322, 324. The first and second shafts 322, 324 define a firstaxis of rotation, the first countershaft 328 defines a second axis ofrotation and the second countershaft 330 defines a third axis ofrotation.

The dual clutch assembly 332 is connectable between the input member 312and the first and second shaft members 322, 324. The dual clutchassembly 332 includes a clutch housing 334 connectable for commonrotation with the input member 312. Further, the dual clutch assembly332 has first and second clutch elements or hubs 336 and 338. Clutchelements 336 and 338 together with the clutch housing 334 are configuredto form a friction clutch, as is known in the art as a dual clutch. Morespecifically, clutch elements 336, 338 and the clutch housing 334 havefriction plates mounted thereon or otherwise coupled thereto thatinteract to form a friction clutch. The clutch element 336 is connectedfor common rotation with the first shaft or member 322 and the clutchelement 338 is connected for common rotation with the second shaft ormember 324. Thus, selective engagement of clutch element 336 with theclutch housing 334 connects the input member 312 for common rotationwith the first shaft member 322. Selective engagement of clutch element338 with the clutch housing 334 connects the input member 312 for commonrotation with the second shaft member 324.

The gearing arrangement 320 also includes a plurality of co-planar,intermeshing gear sets 340, 350, 360, 370, and 380. Co-planar gear set340 includes gear 342, gear 344, and gear 346. Gear 342 is rotatablyfixed and connected for common rotation with the second shaft 324. Gear344 is selectively connectable for common rotation with the firstcountershaft member 328 and intermeshes with gear 342. Gear 346 isselectively connectable for common rotation with the second countershaftmember 330 and intermeshes with gear 342. Gear set 340 is disposedadjacent the end wall 323.

Co-planar gear set 350 includes gear 352, gear 354, and gear 356. Gear352 is rotatably fixed and connected for common rotation with the firstshaft member 322 and intermeshes with gear 354. Gear 354 is supported bythe first countershaft 328, however, gear 354 is not rotationallycoupled to the first countershaft 328. Gear 354 intermeshes with gear356. Gear 356 is selectively connectable for common rotation with thesecond countershaft 330. Gear set 350 is positioned adjacent gear set340.

Co-planar gear set 360 includes gear 362 and gear 364. Gear 362 isrotatably fixed and connected for common rotation with the first shaftmember 322 and intermeshes with gear 364. Gear 364 is selectivelyconnectable for common rotation with the first countershaft 328. Gearset 360 is disposed between end wall 325 and gear set 370.

Co-planar gear set 370 includes gear 372 and gear 374. Gear 372 isrotatably fixed and connected for common rotation with the first shaft322 and intermeshes with gear 374. Gear 374 is selectively connectablefor common rotation with the first countershaft member 328. Gear set 370is located adjacent gear set 360.

Co-planar gear set 380 includes gear 382 and gear 384. Gear 382 isrotatably fixed and connected for common rotation with the first shaftmember 322 and intermeshes with gear 384. Gear 384 is selectivelyconnectable for common rotation with the first countershaft 328. Gearset 380 is positioned adjacent gear set 370. It should be noted thatgear sets 340, 350, 360, 370, 380 can be rearranged in sequence and notdeviate from the intent of the invention.

Further, a first countershaft transfer gear 395 is rotatably fixed andconnected for common rotation with the first countershaft member 328. Asecond countershaft transfer gear 397 is rotatably fixed and connectedfor common rotation with the second countershaft member 330. Firstcountershaft transfer gear 395 is configured to mesh with output member314 and the second countershaft transfer gear 397 is configured to meshwith output member 314. However, the first countershaft transfer gear395 and the second countershaft transfer gear 397 do not mesh with eachother. The first countershaft transfer gear 395 is disposed between gear344 and end wall 323 of the transmission housing 321. The secondcountershaft transfer gear 397 is disposed between gear 354 and end wall323 of the transmission housing 321. The output member 314 is co-planarwith first and second countershaft transfer gears 395, 397 andpositioned between the gear set 340 and end wall 323 of the transmissionhousing 321.

The transmission 300 further includes a plurality of selectivelyactuatable synchronizer assemblies 399A, 399B, 399C, 399D, and 399E.Synchronizers 399A, 399B, 399C, and 399D are single sided synchronizersthat generally include a shift fork (not shown) that is bi-directionallytranslated by an actuator (not shown) into either an engaged position ora neutral or disengaged position. In the present embodiment,synchronizer 399A is selectively actuatable to connect gear 344 forcommon rotation with the first countershaft 328, synchronizer 399B isselectively actuatable to connect gear 346 for common rotation with thesecond countershaft 330, synchronizer 399C is selectively actuatable toconnect gear 356 for common rotation with the second countershaft 330,and synchronizer 399D is selectively actuatable to connect gear 364 forcommon rotation with the first countershaft 328. Synchronizer 399E is adouble sided synchronizer and generally includes a shift fork (notshown) that is bi-directionally translated by an actuator (not shown)into at least two engaged positions and a neutral or disengagedposition. In the present embodiment, synchronizer 399E is selectivelyactuatable to connect for common rotation gear 374 with the firstcountershaft 328 and is selectively actuatable to connect for commonrotation gear 384 with the first countershaft 328.

The transmission 300 is capable of transmitting torque from the inputshaft 312 to the output member 314 in at least five forward torqueratios and at least one reverse torque ratio. Each of the forward torqueratios and the reverse torque ratio is attained by selective engagementof the dual clutch assembly 332 and one or more of the synchronizerassemblies 399A-E. Those skilled in the art will readily understand thata different speed ratio is associated with each torque ratio.

It should be appreciated that each individual gear set 340, 350, 360,370, and 380 provides one or more forward and/or reverse gear ratiosupon selective engagement of the synchronizer assemblies 399A-E.However, which synchronizer and which gear set are associated with aparticular forward or reverse speed ratio may vary without departingfrom the scope of the present invention.

For example, to establish the reverse torque ratio, clutch element 336is engaged to couple the input member 312 with the first shaft member322 and synchronizer 399C is engaged to connect gear 356 to the firstcountershaft 328. More specifically, input torque from the input shaft312 is transferred through the dual clutch assembly 332 to the firstshaft 322, through gear 352 to gear 354, through gear 354 to gear 356,from gear 356 to synchronizer 399C, from synchronizer 399C to secondcountershaft 330, from second countershaft 330 to transfer gear 397,from transfer gear 397 to output gear 314 and from output gear 314 todifferential housing 317 of final drive assembly 316.

To establish a first forward torque ratio (i.e. a 1st gear), clutchelement 336 is engaged to couple the input member 312 with the firstshaft member 322 and synchronizer 399D is activated to couple gear 364to the first countershaft 328. Input torque from the input member 312 istransferred through the dual clutch assembly 332 to the first shaftmember 322 to gear 362. Gear 362 transfers torque to gear 364 whichtransfers the torque to the first countershaft 328 through synchronizer399D, from the first countershaft 328 to transfer gear 395, fromtransfer gear 395 to output gear 314, and from output gear 314 todifferential housing 317 of final drive assembly 316.

To establish a second forward torque ratio (i.e. a 2nd gear), clutchelement 338 is engaged to couple the input member 312 to the secondshaft 324 which rotates gear 342 and synchronizer 399B is activated tocouple gear 346 to the second countershaft member 330. Accordingly,input torque from the input member 312 is transferred through the dualclutch assembly 332 to the second shaft member 324 to gear 342. Gear 342transfers torque to gear 346 which transfers the torque to the secondcountershaft 330 through synchronizer 399B, from the second countershaft330 to transfer gear 397, from transfer gear 397 to output gear 314 andfrom output gear 314 to differential housing 317 of final drive assembly316.

To establish a third forward torque ratio (i.e. a 3rd gear), clutchelement 336 is engaged to couple the input member 312 to the first shaft322 which rotates gear 372 and synchronizer 399E is engaged to couplegear 374 to the first countershaft 328. Accordingly, input torque fromthe input member 312 is transferred through the dual clutch assembly 332to the first shaft 322 to gear 372. Gear 372 transfers torque to gear374 which transfers the torque to the first countershaft 328 throughsynchronizer 399E, from the first countershaft 328 to transfer gear 395,from transfer gear 395 to output gear 314 and from output gear 314 todifferential housing 317 of final drive assembly 316.

To establish a fourth forward torque ratio (i.e. a 4th gear), clutchelement 338 is engaged to couple the input member 312 to the secondshaft member 324 which rotates gear 342 and synchronizer 399A isactivated to couple gear 344 to the first countershaft 328. Thus, inputtorque from the input member 312 is transferred through the dual clutchassembly 332 to the second shaft 324 to gear 342. Gear 342 transferstorque to gear 344 which transfers the torque to the first countershaft328 through synchronizer 399A, from the first countershaft 328 totransfer gear 395, from transfer gear 395 to output gear 314 and fromoutput gear 314 to differential housing 317 of final drive assembly 316.

To establish a fifth forward torque ratio (i.e. a 5th gear), clutchelement 336 is engaged to couple the input member 312 to the first shaft322 which rotates gear 382 and synchronizer 399E is activated to couplegear 384 to the first countershaft 328. Thus, input torque from theinput member 312 is transferred through the dual clutch assembly 332 tothe first shaft 322 to gear 382. Gear 382 transfers torque to gear 384which transfers the torque to the first countershaft 328 throughsynchronizer 399E, from the first countershaft 328 to transfer gear 395,from transfer gear 395 to output gear 314 and from output gear 314 todifferential housing 317 of final drive assembly 316.

Again, it should be appreciated that any one of the gear sets 340, 350,360, 370, and 380 may be changed to produce a certain forward andreverse torque ratio without departing from the scope of the presentinvention.

The present invention contemplates that a variety of torque ratios(i.e., the ratio of torque of the output member 314 to the input member312) are achievable through the selection of tooth counts of the gearsof the transmission 300. This arrangement provides the opportunity toachieve reduced transmission length in comparison with othertransmissions.

Referring to FIG. 5, a multiple speed transmission is generallyindicated by reference number 400. The transmission 400 includes aninput member 412 and a gearing arrangement 420. The gearing arrangement420 includes various shafts or members, co-planar intermeshing gearsets, a dual clutch assembly, and selectively engageable synchronizers,as will be described herein. For example, the gearing arrangement 420includes a first transmission input shaft or member 422, a secondtransmission input shaft or member 424, a first countershaft 428 and asecond countershaft 430. The second shaft or member 424 is a sleeveshaft that is concentric with and overlies the first shaft or member422. The first and second countershafts 428, 430 are spaced apart fromand parallel with the first and second shaft members 422, 424. Moreover,the first and second countershafts 428, 430 are connectable throughadditional gears and/or shafts (not shown) to a final drive assembly(not shown) that is configured to drive a pair of road wheels (notshown). The first and second shafts 422, 424 define a first axis ofrotation, the first countershaft 428 defines a second axis of rotationand the second countershaft 430 defines a third axis of rotation.

A dual clutch assembly 432 is connectable between the input member 412and the first and second shaft members 422, 424. The dual clutchassembly 432 includes a clutch housing 434 connectable for commonrotation with the input member 412. The dual clutch assembly 432 couldbe either a dry or a wet clutch assembly. Further, the dual clutchassembly 432 has first and second clutch elements or hubs 436 and 438.Clutch elements 436 and 438 together with the clutch housing 434 areconfigured to form a friction clutch, as is known in the art as a dualclutch. More specifically, clutch elements 436, 438 and the clutchhousing 434 have friction plates mounted thereon or otherwise coupledthereto that interact to form a friction clutch. The clutch element 436is connected for common rotation with the first shaft or member 422 andthe clutch element 438 is connected for common rotation with the secondshaft or member 424. Thus, selective engagement of clutch element 436with the clutch housing 434 connects the input member 412 for commonrotation with the first shaft member 422. Selective engagement of clutchelement 438 with the clutch housing 434 connects the input member 412for common rotation with the second shaft member 424.

The gearing arrangement 420 also includes a plurality of co-planar,intermeshing gear sets 440, 450, 460, 470, and 480. Co-planar gear sets440, 450, 460, 470, and 480 include intermeshing gear pairs: gear 442and gear 444, gear 452 and gear 454, gear 462, gear 464 and gear 466,gear 472 and gear 474, and gear 482 and gear 484, respectively. In anembodiment of the present invention, gears 442 and 452 are eitherrotatably fixed for common rotation with the second shaft member 424 orare selectively connectable for common rotation with the second shaftmember 424. Gears 462, 472 and 482 are either rotatably fixed for commonrotation with the first shaft member 422 or are selectively connectablefor common rotation with the first shaft member 422. Gears 454 and 466are either rotatably fixed for common rotation with the secondcountershaft 430 or are selectively connectable for common rotation withthe second countershaft 430. Further, gears 444, 464, 474, and 484 areeither rotatably fixed for common rotation with the first countershaft428 or are selectively connectable for common rotation with the firstcountershaft 428. The individual gears of co-planar gear sets 440, 450,460, 470, and 480 are independently and selectively connectable forcommon rotation with the first shaft 422, second shaft member 424, firstcountershaft 428 or second countershaft 430 by synchronizer assemblies,as will be further described hereinafter. Of course, the presentinvention contemplates other selectively actuatable devices other thansynchronizers for connecting gears to shafts.

Referring now to FIG. 6, another embodiment of a multiple speedtransmission is generally indicated by reference number 500. Thetransmission 500 includes an input shaft or member 512 and an outputgear or member 514. The input member 512 is continuously connected withan engine (not shown) or other torque producing machine to provide adriving torque to input member 512. The output member 514 rotatablydrives a final drive assembly 516. More specifically, the final driveassembly 516 includes a differential gear set coupled to and supportedin a differential housing 517. Differential housing 517 is coupled toand is rotatably driven by output member 514. Further, differentialhousing 517 transfers torque delivered by output member 514 to thedifferential gear set that is rotatably coupled to first and second sideaxles 518, 519, and on to road wheels (not shown) coupled to side axles518, 519.

The transmission 500 includes a gearing arrangement 520 that is at leastpartially enclosed by a housing 521. The housing 521 includes end walls523 and 525. End wall 523 is located on a front or side of thetransmission 500 proximate a dual clutch assembly 532 and end wall 525is located on an opposite side of the transmission housing 521 than endwall 525. As in the embodiment described above, the gearing arrangement520 of transmission 500 includes a first transmission input shaft ormember 522, a second transmission input shaft or member 524, a firstcountershaft 528 and a second countershaft 530. The second shaft ormember 524 is a sleeve shaft that is concentric with and overlies thefirst shaft or member 522. The first and second countershafts 528, 530are each spaced apart from and parallel with the first and second shaftmembers 522, 524. The first and second shafts 522, 524 define a firstaxis of rotation, the first countershaft 528 defines a second axis ofrotation and the second countershaft 530 defines a third axis ofrotation.

A dual clutch assembly 532 is connectable between the input member 512and the first and second shaft members 522, 524. The dual clutchassembly 532 includes a clutch housing 534 connectable for commonrotation with the input member 512. Further, the dual clutch assembly532 has first and second clutch elements or hubs 536 and 538. Clutchelements 536 and 538 together with the clutch housing 534 are configuredto form a friction clutch, as is known in the art as a dual clutch. Morespecifically, clutch elements 536, 538 and the clutch housing 534 havefriction plates mounted thereon or otherwise coupled thereto thatinteract to form a friction clutch. The clutch element 536 is connectedfor common rotation with the first shaft or member 522 and the clutchelement 538 is connected for common rotation with the second shaft ormember 524. Thus, selective engagement of clutch element 536 with theclutch housing 534 connects the input member 512 for common rotationwith the first shaft member 522. Selective engagement of clutch element538 with the clutch housing 534 connects the input member 512 for commonrotation with the second shaft member 524.

The gearing arrangement 520 also includes a plurality of co-planar,intermeshing gear sets 540, 550, 560, 570, and 580. Co-planar gear set540 includes gear 542 and gear 544. Gear 542 is rotatably fixed andconnected for common rotation with the second shaft 524. Gear 544 isselectively connectable for common rotation with the first countershaftmember 528 and intermeshes with gear 542. Gear set 540 is disposedadjacent the end wall 523.

Co-planar gear set 550 includes gear 552 and gear 554. Gear 552 isrotatably fixed and connected for common rotation with the second shaftmember 524 and intermeshes with gear 554. Gear 554 is selectivelyconnectable for common rotation with the second countershaft 530. Gearset 550 is positioned adjacent gear set 540.

Co-planar gear set 560 includes gear 562, gear 564, and gear 566. Gear562 is rotatably fixed and connected for common rotation with the firstshaft member 522 and intermeshes with gear 564. Gear 564 is selectivelyconnectable for common rotation with the first countershaft 528 andintermeshes with gear 566. Gear 566 is selectively connectable forcommon rotation with the second countershaft 530. Gear set 560 isdisposed adjacent gear set 550.

Co-planar gear set 570 includes gear 572 and gear 574. Gear 572 isrotatably fixed and connected for common rotation with the first shaft522 and intermeshes with gear 574. Gear 574 is selectively connectablefor common rotation with the first countershaft member 528. Gear set 570is located adjacent gear set 560.

Co-planar gear set 580 includes gear 582 and gear 584. Gear 582 isrotatably fixed and connected for common rotation with the first shaft522 and intermeshes with gear 584. Gear 584 is selectively connectablefor common rotation with the first countershaft member 528. Gear set 580is located adjacent gear set 570 and end wall 525. It should be notedthat gear sets 540, 550, 560, 570, and 580 can be rearranged in sequenceand not deviate from the intent of the invention.

Further, a first countershaft transfer gear 595 is rotatably fixed andconnected for common rotation with the first countershaft member 528. Asecond countershaft transfer gear 597 is rotatably fixed and connectedfor common rotation with the second countershaft member 530. Firstcountershaft transfer gear 595 is configured to mesh with output member514 and the second countershaft transfer gear 597 is configured to meshwith output member 514. However, the first countershaft transfer gear595 and the second countershaft transfer gear 597 do not mesh with eachother. The first countershaft transfer gear 595 is disposed between gear544 and end wall 523 of the transmission housing 521. The secondcountershaft transfer gear 597 is disposed between gear 566 and end wall523 of the transmission housing 521. The output member 514 is co-planarwith first and second countershaft transfer gears 595, 597 andpositioned between the gear set 540 and end wall 523 of the transmissionhousing 521.

The transmission 500 further includes a plurality of selectivelyactuatable synchronizer assemblies 599A, 599B, 599C, 599D, and 599E.Synchronizers 599A, 599B, 599C, and 599D are single sided synchronizersthat generally include a shift fork (not shown) that is bi-directionallytranslated by an actuator (not shown) into either an engaged position ora neutral or disengaged position. In the present embodiment,synchronizer 599A is selectively actuatable to connect gear 544 forcommon rotation with the first countershaft 528, synchronizer 599B isselectively actuatable to connect gear 554 for common rotation with thesecond countershaft 530, synchronizer 599C is selectively actuatable toconnect gear 566 for common rotation with the second countershaft 530,and synchronizer 599D is selectively actuatable to connect gear 564 forcommon rotation with the first countershaft 528. Synchronizer 599E is adouble sided synchronizer and generally includes a shift fork (notshown) that is bi-directionally translated by an actuator (not shown)into at least two engaged positions and a neutral or disengagedposition. In the present embodiment, synchronizer 599E is selectivelyactuatable to connect for common rotation gear 574 with the firstcountershaft 528 and is selectively actuatable to connect for commonrotation gear 584 with the first countershaft 528.

The transmission 500 is capable of transmitting torque from the inputshaft 512 to the output member 514 in at least five forward torqueratios and at least one reverse torque ratio. Each of the forward torqueratios and the reverse torque ratio is attained by selective engagementof the dual clutch assembly 532 and one or more of the synchronizerassemblies 599A-E. Those skilled in the art will readily understand thata different speed ratio is associated with each torque ratio.

It should be appreciated that each individual gear set 540, 550, 560,570, and 580 provides one or more forward and/or reverse gear ratiosupon selective engagement of the synchronizer assemblies 599A-E.However, which synchronizer and which gear set are associated with aparticular forward or reverse speed ratio may vary without departingfrom the scope of the present invention.

For example, to establish the reverse torque ratio, clutch element 536is engaged to couple the input member 512 with the first shaft 522 andsynchronizer 599C is engaged to connect gear 566 to the secondcountershaft 530. More specifically, input torque from the input shaft512 is transferred through the dual clutch assembly 532 to the firstshaft 522, through gear 562 to gear 564, through gear 564 to gear 566,from gear 566 to synchronizer 599C, from synchronizer 599C to secondcountershaft 530, from second countershaft 530 to transfer gear 597,from transfer gear 597 to output gear 514 and from output gear 514 todifferential housing 517 of final drive assembly 516.

To establish a first forward torque ratio (i.e. a 1st gear), clutchelement 536 is engaged to couple the input member 512 with the firstshaft member 522 and synchronizer 599D is activated to couple gear 564to the first countershaft 528. Input torque from the input member 512 istransferred through the dual clutch assembly 532 to the first shaftmember 522 to gear 562. Gear 562 transfers torque to gear 564 whichtransfers the torque to the first countershaft 528 through synchronizer599D, from the first countershaft 528 to transfer gear 595, fromtransfer gear 595 to output gear 514, and from output gear 514 todifferential housing 517 of final drive assembly 516.

To establish a second forward torque ratio (i.e. a 2nd gear), clutchelement 538 is engaged to couple the input member 512 to the secondshaft 524 which rotates gear 542 and synchronizer 599A is activated tocouple gear 544 to the first countershaft member 528. Accordingly, inputtorque from the input member 512 is transferred through the dual clutchassembly 532 to the second shaft member 524 to gear 542. Gear 542transfers torque to gear 544 which transfers the torque to the firstcountershaft 528 through synchronizer 599A, from the first countershaft528 to transfer gear 595, from transfer gear 595 to output gear 514 andfrom output gear 514 to differential housing 517 of final drive assembly516.

To establish a third forward torque ratio (i.e. a 3rd gear), clutchelement 536 is engaged to couple the input member 512 to the first shaft522 which rotates gear 572 and synchronizer 599E is engaged to couplegear 574 to the first countershaft 528. Accordingly, input torque fromthe input member 512 is transferred through the dual clutch assembly 532to the first shaft 522 to gear 572. Gear 572 transfers torque to gear574 which transfers the torque to the first countershaft 528 throughsynchronizer 599E, from the first countershaft 528 to transfer gear 595,from transfer gear 595 to output gear 514 and from output gear 514 todifferential housing 517 of final drive assembly 516.

To establish a fourth forward torque ratio (i.e. a 4th gear), clutchelement 538 is engaged to couple the input member 512 to the secondshaft member 524 which rotates gear 552 and synchronizer 599B isactivated to couple gear 554 to the second countershaft 530. Thus, inputtorque from the input member 512 is transferred through the dual clutchassembly 532 to the second shaft 524 to gear 552. Gear 552 transferstorque to gear 554 which transfers the torque to the second countershaft530 through synchronizer 599B, from the second countershaft 530 totransfer gear 597, from transfer gear 597 to output gear 514 and fromoutput gear 514 to differential housing 517 of final drive assembly 516.

To establish a fifth forward torque ratio (i.e. a 5th gear), clutchelement 536 is engaged to couple the input member 512 to the first shaft522 which rotates gear 582 and synchronizer 599E is activated to couplegear 584 to the first countershaft 528. Thus, input torque from theinput member 512 is transferred through the dual clutch assembly 532 tothe first shaft 522 to gear 582. Gear 582 transfers torque to gear 584which transfers the torque to the first countershaft 528 throughsynchronizer 599E, from the first countershaft 528 to transfer gear 595,from transfer gear 595 to output gear 514 and from output gear 514 todifferential housing 517 of final drive assembly 516.

Again, it should be appreciated that any one of the gear sets 540, 550,560, 570, and 580 may be changed to produce a certain forward andreverse torque ratio without departing from the scope of the presentinvention.

The present invention contemplates that a variety of torque ratios(i.e., the ratio of torque of the output member 514 to the input member512) are achievable through the selection of tooth counts of the gearsof the transmission 500. This arrangement provides the opportunity toachieve reduced transmission length in comparison with othertransmissions.

Referring to FIG. 7, a multiple speed transmission is generallyindicated by reference number 600. The transmission 600 includes aninput member 612 and a gearing arrangement 620. The gearing arrangement620 includes various shafts or members, co-planar intermeshing gearsets, a dual clutch assembly, and selectively engageable synchronizers,as will be described herein. For example, the gearing arrangement 620includes a first transmission input shaft or member 622, a secondtransmission input shaft or member 624, a first countershaft 628 and asecond countershaft 630. The second shaft or member 624 is a sleeveshaft that is concentric with and overlies the first shaft or member622. The first and second countershafts 628, 630 are spaced apart fromand parallel with the first and second shaft members 622, 624. Moreover,the first and second countershafts 628, 630 are connectable throughadditional gears and/or shafts (not shown) to a final drive assembly(not shown) that is configured to drive a pair of road wheels (notshown). The first and second shafts 622, 624 define a first axis ofrotation, the first countershaft 628 defines a second axis of rotationand the second countershaft 630 defines a third axis of rotation.

A dual clutch assembly 632 is connectable between the input member 612and the first and second shaft members 622, 624. The dual clutchassembly 632 includes a clutch housing 634 connectable for commonrotation with the input member 612. The dual clutch assembly 632 couldbe either a dry or a wet clutch assembly. Further, the dual clutchassembly 632 has first and second clutch elements or hubs 636 and 638.Clutch elements 636 and 638 together with the clutch housing 634 areconfigured to form a friction clutch, as is known in the art as a dualclutch. More specifically, clutch elements 636, 638 and the clutchhousing 634 have friction plates mounted thereon or otherwise coupledthereto that interact to form a friction clutch. The clutch element 636is connected for common rotation with the first shaft or member 622 andthe clutch element 638 is connected for common rotation with the secondshaft or member 624. Thus, selective engagement of clutch element 636with the clutch housing 634 connects the input member 612 for commonrotation with the first shaft member 622. Selective engagement of clutchelement 638 with the clutch housing 634 connects the input member 612for common rotation with the second shaft member 624.

The gearing arrangement 620 also includes a plurality of co-planar,intermeshing gear sets 640, 650, 660, and 670. Co-planar gear sets 640,650, 660, and 670 include intermeshing gear pairs: gear 642, gear 644,and gear 646, gear 652, gear 654, and gear 656, gear 662 and gear 664,and gear 672 and gear 674, respectively. In an embodiment of the presentinvention, gear 642 is either rotatably fixed for common rotation withthe second shaft member 624 or is selectively connectable for commonrotation with the second shaft member 624. Gears 652, 662, and 672 areeither rotatably fixed for common rotation with the first shaft member622 or are selectively connectable for common rotation with the firstshaft member 622. Gears 646 and 656 are either rotatably fixed forcommon rotation with the second countershaft 630 or are selectivelyconnectable for common rotation with the second countershaft 630.Further, gears 644, 654, 664, and 674 are either rotatably fixed forcommon rotation with the first countershaft 628 or are selectivelyconnectable for common rotation with the first countershaft 628. Theindividual gears of co-planar gear sets 640, 650, 660, and 670 areindependently and selectively connectable for common rotation with thefirst shaft member 622, second shaft member 624, first countershaft 628or second countershaft 630 by synchronizer assemblies (not shown). Ofcourse, the present invention contemplates other selectively actuatabledevices other than synchronizers for connecting gears to shafts.

Referring now to FIG. 8, another embodiment of a multiple speedtransmission is generally indicated by reference number 700. Thetransmission 700 includes an input shaft or member 712 and an outputgear or member 714. The input member 712 is continuously connected withan engine (not shown) or other torque producing machine to provide adriving torque to input member 712. The output member 714 rotatablydrives a final drive assembly 716. More specifically, the final driveassembly 716 includes a differential gear set coupled to and supportedin a differential housing 717. Differential housing 717 is coupled toand is rotatably driven by output member 714. Further, differentialhousing 717 transfers torque delivered by output member 714 to thedifferential gear set that is rotatably coupled to first and second sideaxles 718, 719, and on to road wheels (not shown) coupled to side axles718, 719.

The transmission 700 includes a gearing arrangement 720 that is at leastpartially enclosed by a housing 721. The housing 721 includes end walls723 and 725. End wall 723 is located on a front or side of thetransmission 700 proximate a dual clutch assembly 732 and end wall 725is located on an opposite side of the transmission housing 721 than endwall 725. As in the embodiment described above, the gearing arrangement720 of transmission 700 includes a first transmission input shaft ormember 722, a second transmission input shaft or member 724, a firstcountershaft 728 and a second countershaft 730. The second shaft ormember 724 is a sleeve shaft that is concentric with and overlies thefirst shaft or member 722. The first and second countershafts 728, 730are each spaced apart from and parallel with the first and second shaftmembers 722, 724. The first and second shafts 722, 724 define a firstaxis of rotation, the first countershaft 728 defines a second axis ofrotation and the second countershaft 730 defines a third axis ofrotation.

A dual clutch assembly 732 is connectable between the input member 712and the first and second shaft members 722, 724. The dual clutchassembly 732 includes a clutch housing 734 connectable for commonrotation with the input member 712. Further, the dual clutch assembly732 has first and second clutch elements or hubs 736 and 738. Clutchelements 736 and 738 together with the clutch housing 734 are configuredto form a friction clutch, as is known in the art as a dual clutch. Morespecifically, clutch elements 736, 738 and the clutch housing 734 havefriction plates mounted thereon or otherwise coupled thereto thatinteract to form a friction clutch. The clutch element 736 is connectedfor common rotation with the first shaft or member 722 and the clutchelement 738 is connected for common rotation with the second shaft ormember 724. Thus, selective engagement of clutch element 736 with theclutch housing 734 connects the input member 712 for common rotationwith the first shaft member 722. Selective engagement of clutch element738 with the clutch housing 734 connects the input member 712 for commonrotation with the second shaft member 724.

The gearing arrangement 720 also includes a plurality of co-planar,intermeshing gear sets 740, 750, 760, and 770. Co-planar gear set 740includes gear 742, gear 744, and gear 746. Gear 742 is rotatably fixedand connected for common rotation with the second shaft 724. Gear 744 isselectively connectable for common rotation with the first countershaftmember 728 and intermeshes with gear 742. Gear 746 is selectivelyconnectable for common rotation with the second countershaft member 730and intermeshes with gear 742. Gear set 740 is disposed adjacent the endwall 723.

Co-planar gear set 750 includes gear 752, gear 754, and gear 756. Gear752 is rotatably fixed and connected for common rotation with the firstshaft member 722 and intermeshes with gear 754. Gear 754 is selectivelyconnectable for common rotation with the first countershaft 728. Gear756 is selectively connectable for common rotation with the secondcountershaft 730 and intermeshes with gear 754. Gear set 750 ispositioned adjacent gear set 740.

Co-planar gear set 760 includes gear 762 and gear 764. Gear 762 isrotatably fixed and connected for common rotation with the first shaftmember 722 and intermeshes with gear 764. Gear 764 is selectivelyconnectable for common rotation with the first countershaft 728. Gearset 760 is disposed adjacent gear set 750.

Co-planar gear set 770 includes gear 772 and gear 774. Gear 772 isrotatably fixed and connected for common rotation with the first shaft722 and intermeshes with gear 774. Gear 774 is selectively connectablefor common rotation with the first countershaft member 728. Gear set 770is located between gear set 760 and end wall 725. It should be notedthat gear sets 740, 750, 760, and 770 can be rearranged in sequence andnot deviate from the intent of the invention.

Further, a first countershaft transfer gear 795 is rotatably fixed andconnected for common rotation with the first countershaft member 728. Asecond countershaft transfer gear 797 is rotatably fixed and connectedfor common rotation with the second countershaft member 730. Firstcountershaft transfer gear 795 is configured to mesh with output member714 and the second countershaft transfer gear 797 is configured to meshwith output member 714. However, the first countershaft transfer gear795 and the second countershaft transfer gear 797 do not mesh with eachother. The first countershaft transfer gear 795 is disposed between gear744 and end wall 723 of the transmission housing 721. The secondcountershaft transfer gear 797 is disposed between gear 746 and end wall723 of the transmission housing 721. The output member 714 is co-planarwith first and second countershaft transfer gears 795, 797 andpositioned between the gear set 740 and end wall 723 of the transmissionhousing 721.

The transmission 700 further includes a plurality of selectivelyactuatable synchronizer assemblies 799A, 799B, 799C, 799D, and 799E.Synchronizers 799A, 799B, 799C, and 799D are single sided synchronizersthat generally include a shift fork (not shown) that is bi-directionallytranslated by an actuator (not shown) into either an engaged position ora neutral or disengaged position. In the present embodiment,synchronizer 799A is selectively actuatable to connect gear 744 forcommon rotation with the first countershaft 728, synchronizer 799B isselectively actuatable to connect gear 746 for common rotation with thesecond countershaft 730, synchronizer 799C is selectively actuatable toconnect gear 756 for common rotation with the second countershaft 730,and synchronizer 799D is selectively actuatable to connect gear 754 forcommon rotation with the first countershaft 728. Synchronizer 799E is adouble sided synchronizer and generally includes a shift fork (notshown) that is bi-directionally translated by an actuator (not shown)into at least two engaged positions and a neutral or disengagedposition. In the present embodiment, synchronizer 799E is selectivelyactuatable to connect for common rotation gear 764 with the firstcountershaft 728 and is selectively actuatable to connect for commonrotation gear 774 with the first countershaft 728.

The transmission 700 is capable of transmitting torque from the inputshaft 712 to the output member 714 in at least five forward torqueratios and at least one reverse torque ratio. Each of the forward torqueratios and the reverse torque ratio is attained by selective engagementof the dual clutch assembly 732 and one or more of the synchronizerassemblies 799A-E. Those skilled in the art will readily understand thata different speed ratio is associated with each torque ratio.

It should be appreciated that each individual gear set 740, 750, 760,and 770 provides one or more forward and/or reverse gear ratios uponselective engagement of the synchronizer assemblies 799A-E. However,which synchronizer and which gear set are associated with a particularforward or reverse speed ratio may vary without departing from the scopeof the present invention.

For example, to establish the reverse torque ratio, clutch element 736is engaged to couple the input member 712 with the first shaft 722 andsynchronizer 799C is engaged to connect gear 756 to the secondcountershaft 730. More specifically, input torque from the input shaft712 is transferred through the dual clutch assembly 732 to the firstshaft 722, through gear 752 to gear 754, through gear 754 to gear 756,from gear 756 to synchronizer 799C, from synchronizer 799C to secondcountershaft 730, from second countershaft 730 to transfer gear 797,from transfer gear 797 to output gear 714 and from output gear 714 todifferential housing 717 of final drive assembly 716.

To establish a first forward torque ratio (i.e. a 1st gear), clutchelement 736 is engaged to couple the input member 712 with the firstshaft member 722 and synchronizer 799D is activated to couple gear 754to the first countershaft 728. Input torque from the input member 712 istransferred through the dual clutch assembly 732 to the first shaftmember 722 to gear 752. Gear 752 transfers torque to gear 754 whichtransfers the torque to the first countershaft 728 through synchronizer799D, from the first countershaft 728 to transfer gear 795, fromtransfer gear 795 to output gear 714, and from output gear 714 todifferential housing 717 of final drive assembly 716.

To establish a second forward torque ratio (i.e. a 2nd gear), clutchelement 738 is engaged to couple the input member 712 to the secondshaft 724 which rotates gear 742 and synchronizer 799B is activated tocouple gear 746 to the second countershaft member 730. Accordingly,input torque from the input member 712 is transferred through the dualclutch assembly 732 to the second shaft member 724 to gear 742. Gear 742transfers torque to gear 746 which transfers the torque to the secondcountershaft 730 through synchronizer 799B, from the second countershaft730 to transfer gear 797, from transfer gear 797 to output gear 714 andfrom output gear 714 to differential housing 717 of final drive assembly716.

To establish a third forward torque ratio (i.e. a 3rd gear), clutchelement 736 is engaged to couple the input member 712 to the first shaft722 which rotates gear 772 and synchronizer 799E is engaged to couplegear 774 to the first countershaft 728. Accordingly, input torque fromthe input member 712 is transferred through the dual clutch assembly 732to the first shaft 722 to gear 772. Gear 772 transfers torque to gear774 which transfers the torque to the first countershaft 728 throughsynchronizer 799E, from the first countershaft 728 to transfer gear 795,from transfer gear 795 to output gear 714 and from output gear 714 todifferential housing 717 of final drive assembly 716.

To establish a fourth forward torque ratio (i.e. a 4th gear), clutchelement 738 is engaged to couple the input member 712 to the secondshaft member 724 which rotates gear 742 and synchronizer 799A isactivated to couple gear 744 to the first countershaft 728. Thus, inputtorque from the input member 712 is transferred through the dual clutchassembly 732 to the second shaft 724 to gear 742. Gear 742 transferstorque to gear 744 which transfers the torque to the first countershaft728 through synchronizer 799A, from the first countershaft 728 totransfer gear 795, from transfer gear 795 to output gear 714 and fromoutput gear 714 to differential housing 717 of final drive assembly 716.

To establish a fifth forward torque ratio (i.e. a 5th gear), clutchelement 736 is engaged to couple the input member 712 to the first shaft722 which rotates gear 762 and synchronizer 799E is activated to couplegear 764 to the first countershaft 728. Thus, input torque from theinput member 712 is transferred through the dual clutch assembly 732 tothe first shaft 722 to gear 762. Gear 762 transfers torque to gear 764which transfers the torque to the first countershaft 728 throughsynchronizer 799E, from the first countershaft 728 to transfer gear 795,from transfer gear 795 to output gear 714 and from output gear 714 todifferential housing 717 of final drive assembly 716.

Again, it should be appreciated that any one of the gear sets 740, 750,760, and 770 may be changed to produce a certain forward and reversetorque ratio without departing from the scope of the present invention.

The present invention contemplates that a variety of torque ratios(i.e., the ratio of torque of the output member 714 to the input member712) are achievable through the selection of tooth counts of the gearsof the transmission 700. This arrangement provides the opportunity toachieve reduced transmission length in comparison with othertransmissions.

While the best modes for carrying out the invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

1. A transmission comprising: a transmission housing; a dual clutchassembly having a clutch housing connectable to a flywheel of an engine,wherein the clutch housing is rotationally supported within thetransmission housing; a first, second, third, fourth, fifth, and sixthgear sets, wherein the first gear set includes a first gear in mesh witha second gear, the second gear set includes a first gear in mesh with asecond gear, the third gear set includes a first gear in mesh with asecond gear, the fourth gear set includes a first gear in mesh with asecond gear, the fifth gear set includes a first gear in mesh with asecond gear, and the sixth gear set includes a first gear in mesh with asecond gear and a third gear in mesh with the second gear; a firsttransmission input member rotatably supported in the transmissionhousing and wherein each of the first gear of the third, fourth, fifth,and sixth gear sets are rotatably fixed for common rotation with thefirst transmission input member; a second transmission input memberrotatably supported in the transmission housing, wherein each of thefirst gear of the first and second gear sets are rotatably fixed forcommon rotation with the second transmission input member and whereinthe second transmission input member is concentric with the firsttransmission input member and at least partially surrounds the firsttransmission input member; a first countershaft rotatably supportedwithin the transmission housing and spaced apart from and parallel withthe first and second transmission input members, wherein the each of thesecond gear of the second and third gear sets are selectivelyconnectable for common rotation with the first countershaft and thethird gear of the sixth gear set is selectively connectable for commonrotation with the first countershaft; a second countershaft rotatablysupported within the transmission housing and spaced apart from andparallel with the first and second transmission input members, whereineach of the second gear of the first and fourth gear sets areselectively connectable for common rotation with the second countershaftand the second gear of the sixth gear set is supported on and rotatableabout the second countershaft; five synchronizer assemblies forselectively coupling at least one of the gears of the first, second,third, and fourth gear sets with at least one of the first countershaftand the second countershaft, wherein the selective engagement of thedual clutch assembly interconnects the dual clutch housing with at leastone of the first and the second transmission input members and theselective engagement of at least one of the five synchronizer assembliesestablishes at least one of five forward speed ratios.
 2. Thetransmission of claim 1 wherein a first of the five synchronizerassemblies selectively connects the second gear of the second gear setto the first countershaft.
 3. The transmission of claim 2 wherein asecond of the five synchronizer assemblies selectively connects thesecond gear of the first gear set to the second countershaft.
 4. Thetransmission of claim 3 wherein a third of the five synchronizerassemblies selectively connects the second gear of the third gear set tothe first countershaft.
 5. The transmission of claim 4 wherein a fourthof the five synchronizer assemblies selectively connects at least one ofthe second gear of the fourth gear set and the second gear of the fifthgear set to the second countershaft.
 6. The transmission of claim 5wherein a fifth of the five synchronizer assemblies selectively connectsthe third gear of the sixth gear set to the first countershaft.
 7. Thetransmission of claim 1 wherein the first gear set is adjacent the dualclutch assembly, the second gear set is adjacent the first gear set, thethird gear set is adjacent the second gear set, the fourth gear set isadjacent the third gear set, the fifth gear set is adjacent the fourthgear set, and the sixth gear set is between an end wall of thetransmission housing and the fifth gear set.
 8. The transmission ofclaim 1 wherein the first gear set provides a second forward speedratio, the second gear set provides a fourth forward speed ratio, thethird gear set provides a first forward speed ratio, the fourth gear setprovides a fifth forward speed ratio, the fifth gear set provides athird forward gear ratio, and the sixth gear set provides a reversespeed ratio.
 9. A transmission comprising: a transmission housing; adual clutch assembly having a clutch housing connectable to a flywheelof an engine, wherein the clutch housing is rotationally supportedwithin the transmission housing; a first, second, third, fourth, andfifth gear sets, wherein the first gear set includes a first gear inmesh with a second gear and a third gear, the second gear set includes afirst gear in mesh with a second gear and the second gear in mesh with athird gear, the third gear set includes a first gear in mesh with asecond gear, the fourth gear set includes a first gear in mesh with asecond gear, and the fifth gear set includes a first gear in mesh with asecond gear; a first transmission input member rotatably supported inthe transmission housing and wherein each of the first gear of thesecond, third, fourth, and fifth gear sets are rotatably fixed forcommon rotation with the first transmission input member; a secondtransmission input member rotatably supported in the transmissionhousing, wherein the first gear of the first gear set is rotatably fixedfor common rotation with the second transmission input member andwherein the second transmission input member is concentric with thefirst transmission input member and at least partially surrounds thefirst transmission input member; a first countershaft rotatablysupported within the transmission housing and spaced apart from andparallel with the first and second transmission input members, whereinthe each of the third gear of the first and second gear sets areselectively connectable for common rotation with the first countershaft;a second countershaft rotatably supported within the transmissionhousing and spaced apart from and parallel with the first and secondtransmission input members, wherein each of the second gear of thefirst, third, fourth, and fifth gear sets are selectively connectablefor common rotation with the second countershaft and the second gear ofthe second gear set is supported on and rotatable about the secondcountershaft; five synchronizer assemblies for selectively coupling atleast one of the gears of the first, second, third, fourth, and fifthgear sets with at least one of the first countershaft and the secondcountershaft, wherein the selective engagement of the dual clutchassembly interconnects the dual clutch housing with at least one of thefirst and the second transmission input members and the selectiveengagement of at least one of the five synchronizer assembliesestablishes at least one of five forward speed ratios.
 10. Thetransmission of claim 9 wherein a first of the five synchronizerassemblies selectively connects the third gear of the first gear set tothe first countershaft.
 11. The transmission of claim 10 wherein asecond of the five synchronizer assemblies selectively connects thesecond gear of the first gear set to the second countershaft.
 12. Thetransmission of claim 11 wherein a third of the five synchronizerassemblies selectively connects the third gear of the second gear set tothe first countershaft.
 13. The transmission of claim 12 wherein afourth of the five synchronizer assemblies selectively connects at leastone of the second gear of the third gear set and the second gear of thefourth gear set to the second countershaft.
 14. The transmission ofclaim 13 wherein a fifth of the five synchronizer assemblies selectivelyconnects the second gear of the fifth gear set to the secondcountershaft.
 15. The transmission of claim 9 wherein the first gear setis adjacent the dual clutch assembly, the second gear set is adjacentthe first gear set, the third gear set is adjacent the second gear set,the fourth gear set is adjacent the third gear set, and the fifth gearset is between an end wall of the transmission housing and the fourthgear set.
 16. The transmission of claim 9 wherein the first gear setprovides a second and a fourth forward speed ratio, the second gear setprovides a reverse speed ratio, the third gear set provides a fifthforward speed ratio, the fourth gear set provides a third forward speedratio, and the fifth gear set provides a first forward gear ratio.
 17. Atransmission comprising: a transmission housing; a dual clutch assemblyhaving a clutch housing connectable to a flywheel of an engine, whereinthe clutch housing is rotationally supported within the transmissionhousing; a first, second, third, and fourth gear sets, wherein the firstgear set includes a first gear in mesh with a second gear, the secondgear set includes a first gear in mesh with a second gear and the secondgear in mesh with a third gear, the third gear set includes a first gearin mesh with a second gear, and the fourth gear set includes a firstgear in mesh with a second gear; a first transmission input memberrotatably supported in the transmission housing and wherein each of thefirst gear of the second, third, and fourth gear sets are rotatablyfixed for common rotation with the first transmission input member; asecond transmission input member rotatably supported in the transmissionhousing, wherein the first gear of the first gear set is rotatably fixedfor common rotation with the second transmission input member andwherein the second transmission input member is concentric with thefirst transmission input member and at least partially surrounds thefirst transmission input member; a first countershaft rotatablysupported within the transmission housing and spaced apart from andparallel with the first and second transmission input members, whereineach of the second gear of the first gear set and the third gear of thesecond gear set are selectively connectable for common rotation with thefirst countershaft; a second countershaft rotatably supported within thetransmission housing and spaced apart from and parallel with the firstand second transmission input members, wherein each of the second gearof the second, third and fourth gear sets are selectively connectablefor common rotation with the second countershaft; five synchronizerassemblies for selectively coupling at least one of the gears of thefirst, second, third, and fourth gear sets with at least one of thefirst countershaft and the second countershaft, wherein the selectiveengagement of the dual clutch assembly interconnects the dual clutchhousing with at least one of the first and the second transmission inputmembers and the selective engagement of at least one of the fivesynchronizer assemblies establishes at least one of five forward speedratios.
 18. The transmission of claim 17 wherein the first gear setincludes a third gear in mesh with the first gear of the first gear set,and wherein the third gear is selectively engageable for common rotationwith the second countershaft.
 19. The transmission of claim 18 wherein afirst of the five synchronizer assemblies selectively connects thesecond gear of the first gear set to the first countershaft.
 20. Thetransmission of claim 19 wherein a second of the five synchronizerassemblies selectively connects the third gear of the first gear set tothe second countershaft.
 21. The transmission of claim 20 wherein athird of the five synchronizer assemblies selectively connects the thirdgear of the second gear set to the first countershaft.
 22. Thetransmission of claim 21 wherein a fourth of the five synchronizerassemblies selectively connects at least one of the second gear of thethird gear set and the second gear of the fourth gear set to the secondcountershaft.
 23. The transmission of claim 22 wherein a fifth of thefive synchronizer assemblies selectively connects the second gear of thesecond gear set to the second countershaft.
 24. The transmission ofclaim 18 wherein the first gear set is adjacent the dual clutchassembly, the second gear set is adjacent the first gear set, the thirdgear set is adjacent the second gear set, and the fourth gear set isbetween an end wall of the transmission housing and the third gear set.25. The transmission of claim 18 wherein the first gear set provides asecond and a fourth forward speed ratio, the second gear set provides areverse speed ratio and a first forward speed ratio, the third gear setprovides a fifth forward speed ratio, and the fourth gear set provides athird forward speed ratio.
 26. The transmission of claim 17 furthercomprising a fifth gear set which includes a first gear in mesh with asecond gear, and wherein the first gear is fixed for common rotationwith the second transmission input shaft and the second gear isselectively engageable with the second countershaft.
 27. Thetransmission of claim 26 wherein a first of the five synchronizerassemblies selectively connects the second gear of the first gear set tothe first countershaft.
 28. The transmission of claim 27 wherein asecond of the five synchronizer assemblies selectively connects thesecond gear of the fifth gear set to the second countershaft.
 29. Thetransmission of claim 28 wherein a third of the five synchronizerassemblies selectively connects the third gear of the second gear set tothe first countershaft.
 30. The transmission of claim 29 wherein afourth of the five synchronizer assemblies selectively connects at leastone of the second gear of the third gear set and the second gear of thefourth gear set to the second countershaft.
 31. The transmission ofclaim 30 wherein a fifth of the five synchronizer assemblies selectivelyconnects the second gear of the second gear set to the secondcountershaft.
 32. The transmission of claim 26 wherein the fifth gearset is adjacent the dual clutch assembly, the first gear set is adjacentthe fifth gear set, the second gear set is adjacent the first gear set,the third gear set is adjacent the second gear set, and the fourth gearset is between an end wall of the transmission housing and the thirdgear set.
 33. The transmission of claim 26 wherein the first gear setprovides a a fourth forward speed ratio, the second gear set provides areverse speed ratio and a first forward speed ratio, the third gear setprovides a third forward speed ratio, the fourth gear set provides afifth forward speed ratio, and the fifth gear set provides a secondforward speed ratio.